Using your G - Shock MR - G B5000 Series watch is a breeze. For radio - controlled calibration, just make sure the watch is in an area with good signal reception, and it will automatically adjust the time. To pair your watch with your smartphone via Bluetooth®, go to the settings on your phone, turn on Bluetooth, and follow the prompts on the watch to connect. When it comes to water resistance, it can handle up to 200 meters, so you can wear it while swimming or snorkeling. But avoid pressing the buttons underwater. To maintain your watch, clean it regularly with a soft, dry cloth. If it gets dirty, you can use a mild soap and water solution, then dry it thoroughly. Keep it away from extreme temperatures and magnetic fields, as these can affect its performance. Also, if you're not using the watch for a long time, store it in a cool, dry place.